I'm new to ditgtal phography. Last year I bought a D3300. On YouTube Nikon has a free school that will show you how to work your camera. I also bought a book called Nikon D3300 for Dummies. Nikon will also tell you to shoot RAW if you want to make prints at your local drug store you have to shoot in JEPG. Nikon also included a NEX 2 program I down loaded on my new laptop. I don't know a lot about computers but I can tell you the new windows and nex2 don't seem to get along. Or most likely I don't know how to use it. But eatherway its a pain in the ass for me. Don't get sucked in to believing that the kit 18-55 lens is junk. If I'm not mistaken the D3400 comes with the new AF-P 18-55 with improved glass and faster focus. If you don't push the lens it will do a good jop. I bought a new 35mm & 50mm Nikon prime lens. I shot all my Christmas pictures with the 35mm they all came out very good. I bought a Nikon speed light ( flash ) I think I have used it once. The mistake I made was I bought it first then read the reviews. I have a very nice flash that I paid about $150.00 more than I should have. I also bought some UV filters I'll tell ya now don't waste your money. I bought a battery grip that turned out to be one of the best buys I've made. I don't know how many pictures I'm getting on two batteries but its a lot. The extra shutter button is great. They arnt that expensive. Mine came with a battery & charger if I rember its a Vivatr for under $40. That's about the price of one Nikon battery. I don't like camera neck straps its just to mutch advertising. So I use a hand grip. I have bought 3 before I found one I like.
The guide is very easy to use once you catch on. Its not not all that different than film except on steroids. As I said YouTube is full of tuturals. They are for the most part very good. UH is also a great source of info. I have never been a flower guy but after seeing some photos on UH I'm changing my mind. Have fun